estimate

Etymology

Borrowed from Latin aestimatus, past participle of aestimō, older form aestumo (“to value, rate, esteem”); from Old Latin *ais-temos (“one who cuts copper”), meaning one in the Roman Republic who mints money. See also the doublet esteem, as well as aim.

noun

1. A rough calculation or assessment of the value, size, or cost of something.
2. (construction and business) A document (or verbal notification) specifying how much a job is likely to cost.
   “They know our boats will stand up to their work,” said Willison, “and that counts for a good deal. A low estimate from us doesn't mean scamped work, but just that we want to keep the yard busy over a slack time.” 1928, Lawrence R. Bourne, chapter 3, in Well Tackled!
3. An upper limitation on some positive quantity.
   The desired norm estimate is now obtained from the identity... [referring to an earlier statement saying that a certain norm is less than or equal to a certain expression] 1992, Louis de Branges, “The convergence of Euler functions”, in Journal of Functional Analysis, →DOI, page 185

verb

1. To calculate roughly, often from imperfect data.
   I estimate that I need 400 board feet of lumber to complete a job, and then order 350 because I do not want a surplus, or perhaps order 450 because I do not want to make any subsequent orders. 1965, Ian Hacking, Logic of Statistical Inference
   Higher real prices for durables are estimated to have reduced their consumption per capita by 1.09% in 1930, […] 2003, Alexander J. Field, Gregory Clark, William A. Sundstrom, Research in Economic History
2. To judge and form an opinion of the value of, from imperfect data.
   It is always very difficult to estimate the age in which you are living. 1870, John Campbell Shairp, Culture and Religion in Some of Their Relations